73c5de0051
In a multi device setup, the chunk allocator currently always allocates chunks on the devices in the same order. This leads to a very uneven distribution, especially with RAID1 or RAID10 and an uneven number of devices. This patch always sorts the devices before allocating, and allocates the stripes on the devices with the most available space, as long as there is enough space available. In a low space situation, it first tries to maximize striping. The patch also simplifies the allocator and reduces the checks for corner cases. The simplification is done by several means. First, it defines the properties of each RAID type upfront. These properties are used afterwards instead of differentiating cases in several places. Second, the old allocator defined a minimum stripe size for each block group type, tried to find a large enough chunk, and if this fails just allocates a smaller one. This is now done in one step. The largest possible chunk (up to max_chunk_size) is searched and allocated. Because we now have only one pass, the allocation of the map (struct map_lookup) is moved down to the point where the number of stripes is already known. This way we avoid reallocation of the map. We still avoid allocating stripes that are not a multiple of STRIPE_SIZE.
213 lines
5.9 KiB
C
213 lines
5.9 KiB
C
/*
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* Copyright (C) 2007 Oracle. All rights reserved.
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public
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* License v2 as published by the Free Software Foundation.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* General Public License for more details.
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*
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* You should have received a copy of the GNU General Public
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* License along with this program; if not, write to the
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* Free Software Foundation, Inc., 59 Temple Place - Suite 330,
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* Boston, MA 021110-1307, USA.
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*/
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#ifndef __BTRFS_VOLUMES_
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#define __BTRFS_VOLUMES_
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#include <linux/bio.h>
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#include <linux/sort.h>
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#include "async-thread.h"
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#define BTRFS_STRIPE_LEN (64 * 1024)
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struct buffer_head;
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struct btrfs_pending_bios {
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struct bio *head;
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struct bio *tail;
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};
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struct btrfs_device {
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struct list_head dev_list;
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struct list_head dev_alloc_list;
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struct btrfs_fs_devices *fs_devices;
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struct btrfs_root *dev_root;
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/* regular prio bios */
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struct btrfs_pending_bios pending_bios;
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/* WRITE_SYNC bios */
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struct btrfs_pending_bios pending_sync_bios;
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int running_pending;
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u64 generation;
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int writeable;
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int in_fs_metadata;
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int missing;
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spinlock_t io_lock;
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struct block_device *bdev;
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/* the mode sent to blkdev_get */
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fmode_t mode;
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char *name;
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/* the internal btrfs device id */
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u64 devid;
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/* size of the device */
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u64 total_bytes;
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/* size of the disk */
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u64 disk_total_bytes;
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/* bytes used */
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u64 bytes_used;
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/* optimal io alignment for this device */
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u32 io_align;
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/* optimal io width for this device */
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u32 io_width;
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/* minimal io size for this device */
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u32 sector_size;
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/* type and info about this device */
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u64 type;
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/* physical drive uuid (or lvm uuid) */
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u8 uuid[BTRFS_UUID_SIZE];
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struct btrfs_work work;
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};
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struct btrfs_fs_devices {
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u8 fsid[BTRFS_FSID_SIZE]; /* FS specific uuid */
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/* the device with this id has the most recent copy of the super */
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u64 latest_devid;
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u64 latest_trans;
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u64 num_devices;
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u64 open_devices;
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u64 rw_devices;
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u64 missing_devices;
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u64 total_rw_bytes;
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struct block_device *latest_bdev;
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/* all of the devices in the FS, protected by a mutex
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* so we can safely walk it to write out the supers without
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* worrying about add/remove by the multi-device code
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*/
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struct mutex device_list_mutex;
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struct list_head devices;
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/* devices not currently being allocated */
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struct list_head alloc_list;
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struct list_head list;
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struct btrfs_fs_devices *seed;
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int seeding;
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int opened;
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/* set when we find or add a device that doesn't have the
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* nonrot flag set
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*/
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int rotating;
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};
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struct btrfs_bio_stripe {
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struct btrfs_device *dev;
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u64 physical;
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u64 length; /* only used for discard mappings */
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};
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struct btrfs_multi_bio {
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atomic_t stripes_pending;
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bio_end_io_t *end_io;
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struct bio *orig_bio;
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void *private;
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atomic_t error;
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int max_errors;
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int num_stripes;
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struct btrfs_bio_stripe stripes[];
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};
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struct btrfs_device_info {
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struct btrfs_device *dev;
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u64 dev_offset;
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u64 max_avail;
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u64 total_avail;
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};
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struct map_lookup {
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u64 type;
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int io_align;
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int io_width;
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int stripe_len;
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int sector_size;
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int num_stripes;
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int sub_stripes;
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struct btrfs_bio_stripe stripes[];
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};
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int btrfs_account_dev_extents_size(struct btrfs_device *device, u64 start,
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u64 end, u64 *length);
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#define btrfs_multi_bio_size(n) (sizeof(struct btrfs_multi_bio) + \
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(sizeof(struct btrfs_bio_stripe) * (n)))
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int btrfs_alloc_dev_extent(struct btrfs_trans_handle *trans,
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struct btrfs_device *device,
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u64 chunk_tree, u64 chunk_objectid,
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u64 chunk_offset, u64 start, u64 num_bytes);
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int btrfs_map_block(struct btrfs_mapping_tree *map_tree, int rw,
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u64 logical, u64 *length,
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struct btrfs_multi_bio **multi_ret, int mirror_num);
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int btrfs_rmap_block(struct btrfs_mapping_tree *map_tree,
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u64 chunk_start, u64 physical, u64 devid,
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u64 **logical, int *naddrs, int *stripe_len);
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int btrfs_read_sys_array(struct btrfs_root *root);
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int btrfs_read_chunk_tree(struct btrfs_root *root);
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int btrfs_alloc_chunk(struct btrfs_trans_handle *trans,
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struct btrfs_root *extent_root, u64 type);
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void btrfs_mapping_init(struct btrfs_mapping_tree *tree);
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void btrfs_mapping_tree_free(struct btrfs_mapping_tree *tree);
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int btrfs_map_bio(struct btrfs_root *root, int rw, struct bio *bio,
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int mirror_num, int async_submit);
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int btrfs_read_super_device(struct btrfs_root *root, struct extent_buffer *buf);
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int btrfs_open_devices(struct btrfs_fs_devices *fs_devices,
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fmode_t flags, void *holder);
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int btrfs_scan_one_device(const char *path, fmode_t flags, void *holder,
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struct btrfs_fs_devices **fs_devices_ret);
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int btrfs_close_devices(struct btrfs_fs_devices *fs_devices);
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int btrfs_close_extra_devices(struct btrfs_fs_devices *fs_devices);
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int btrfs_add_device(struct btrfs_trans_handle *trans,
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struct btrfs_root *root,
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struct btrfs_device *device);
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int btrfs_rm_device(struct btrfs_root *root, char *device_path);
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int btrfs_cleanup_fs_uuids(void);
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int btrfs_num_copies(struct btrfs_mapping_tree *map_tree, u64 logical, u64 len);
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int btrfs_unplug_page(struct btrfs_mapping_tree *map_tree,
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u64 logical, struct page *page);
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int btrfs_grow_device(struct btrfs_trans_handle *trans,
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struct btrfs_device *device, u64 new_size);
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struct btrfs_device *btrfs_find_device(struct btrfs_root *root, u64 devid,
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u8 *uuid, u8 *fsid);
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int btrfs_shrink_device(struct btrfs_device *device, u64 new_size);
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int btrfs_init_new_device(struct btrfs_root *root, char *path);
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int btrfs_balance(struct btrfs_root *dev_root);
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void btrfs_unlock_volumes(void);
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void btrfs_lock_volumes(void);
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int btrfs_chunk_readonly(struct btrfs_root *root, u64 chunk_offset);
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int find_free_dev_extent(struct btrfs_trans_handle *trans,
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struct btrfs_device *device, u64 num_bytes,
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u64 *start, u64 *max_avail);
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#endif
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